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BackTable / VI / Podcast / Transcript #280
Podcast Transcript: Current Controversies in Prostatic Artery Embolization
with Dr. Sam Mouli
In this episode, host Dr. Michael Barraza interviews interventional radiologist Dr. Samdeep Mouli about controversies in prostate artery embolization, including technique, durability, and how we can leverage the data to unite IRs and establish PAE as standard of care. You can read the full transcript below and listen to this episode here on BackTable.com.
Table of Contents
(1) The Evolution of Prostate Artery Embolization
(2) Standardizing Prostate Artery Embolization
(3) The Case for Early Prostate Artery Embolization
(4) The Role of Urologists and Patient Self-Referral in PAE
(5) Pre-Procedural Imaging for Prostate Artery Embolization
(6) Cone Beam CT in Prostate Artery Embolization
(7) PAE Technique: Embolic Agents, Collaterals & Vasodilators
(8) Advanced Techniques in Prostate Artery Embolization
(9) Retreatment Rates Following Prostate Artery Embolization
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[Dr. Michael Barraza]
I'm thrilled to welcome back Dr. Sam Mouli from Northwestern University. Sam, thanks for joining us.
[Dr. Sam Mouli]
Thank you for having me.
[Dr. Michael Barraza]
How's it going this week?
[Dr. Sam Mouli]
Very good. How's it going with you guys?
[Dr. Michael Barraza]
Pretty good. I'm off this week, which is good. As I told you earlier, you know the drill sometimes. Even when you're off, you're on. I had to go take care of a couple cases today and got a couple tomorrow when I'm off. That's the job.
[Dr. Sam Mouli]
Exactly, that's the job.
[Dr. Michael Barraza]
That's right. Sam, one of the things I wanted to do before we get into our topic, which I should say we're going to be talking about controversies in PAE, prostatic artery embolization. I wanted to ask you a bit. I noticed you're the director of translational interventional radiology research at Northwestern. I want you to tell me a little bit about that position, what that entails, and some of the things that you and your group are working on that you're excited about.
[Dr. Sam Mouli]
We've developed this program over the last 10 years, and our goal is to do research in the interventional space that is not just basic science, not just animal work, but things that we can directly translate to clinical trials and treating patients. That's really the goal of what we do in the lab. One of the big things that is an open secret, I think, in IR is we're looking for new applications for Y90 radioembolization. We're doing studies on the brain. We're doing studies on the prostate. That's a lot of the work that we are working on currently and starting some first-in-man clinical trials in the next couple of years in that space.
[Dr. Michael Barraza]
Oh, no kidding. That's exciting. You and I have talked about some of this before about doing this for prostate cancer, and I think the applications are there. I'm excited to see what you guys have coming through.
[Dr. Sam Mouli]
Yes. So are we, eagerly awaiting to get started.
(1) The Evolution of Prostate Artery Embolization
[Dr. Michael Barraza]
Yes, I bet. Sam, we're going to be talking about PAE. We already knew at the beginning we were going to talk about PAE, and usually what I do is I send out an email. It's like, "Hey, this is what we're going to talk about." For our listeners, I emailed Sam. Sam is one of the main guys for PAE right now in terms of research. I figured I better off just asking him, "What do you want to talk about?" One of the ideas he had suggested was some controversies in PAE. Certainly, they're there. We've done probably four or five podcasts on PAE.
Looking back on the first one, which is probably four or five years ago, the landscape has completely changed. I would say we're approaching this being, I don't want to say mainstream procedure, but it is a lot more common when I first interviewed Ari Isaacson and Sandeep Bagla on this. Then that there were really only a handful of people doing it in a handful of places. Now you can find somebody that does it in just about every major city.
[Dr. Sam Mouli]
Yes, we've come a long way since the beginning. I would say that Ari and Sandeep did the lion's share of work along with several other investigators from around the US and around the world to really democratize PAE for a variety of patients and allow us to really refine the techniques. Their lead has allowed industry to follow and develop new tools to make it easier to do. What we had 10 years ago compared to what we have today is a huge, huge change and so a lot of people are getting more and more comfortable in this space and more and more comfortable treating patients.
I think it's very clear from all of the data that we have from multiple trials that this is really something that should be offered to all patients with BPH who are considering surgical resection of their prostate. It's right up there with the other minimally invasive therapies.
[Dr. Michael Barraza]
Now, Sam, I feel like we've had some very convincing data for years now. We all know the issues with the AUA guidelines. I don't think we need to get into that. Do you think, has there been anything major in terms of data in the last 6 to 12 months that goes beyond what we already have?
[Dr. Sam Mouli]
Yes, I think the two biggest papers that came out in the last year or so, and I'm probably getting the dates incorrect, but we have the long-term studies from both the Portuguese group from Tiago Bilhim's group and then Francisco Carnevale's group that basically come out around the same time showing what the 10-year data for PAE is. I think the two biggest take-home points from those large data series is the durability of symptoms, how long these procedures typically last, and then also the safety profile.
I think the biggest positive for PAE and what I share with patients is amongst all of the minimally invasive surgical therapies, it's very, very safe. With experience, you can do this with a very great safety profile, especially in comparison to some of the other surgical therapies. We can do this in patients and they don't require a Foley catheter, et cetera. They don't really suffer from sexual dysfunction afterwards, urinary leakage, hematuria, all these other things that you might see with surgical resection. That's really the case to make for why PAE should be pursued maybe first-line instead of surgery because it's just very, very safe in patients.
Additionally, we can see even from those long-term data series that it doesn't preclude a patient from getting any other medical or surgical therapy down the line. Let's say their symptoms progress and they decide to go on to TURP or what have you, all of those options are still available. You haven't lost anything by trying, so to speak.
(2) Standardizing Prostate Artery Embolization
[Dr. Michael Barraza]
Sam, from just our email discussion, preparing for this, you had mentioned you feel pretty strongly about the fact that we need to have some sort of standardization in how PAE is performed. First, I completely agree with you and I think that is probably one of the barriers to making this grow faster is that people out there are doing this in different ways and we're still tweaking it. I just wanted to hear your take on it about where we stand in that process, and basically how long do we have until we feel confident about the best way to do this so that we can all be doing this in a similar manner.
[Dr. Sam Mouli]
I think everybody has a different flavor of doing it right now. I won't really speak to the radial versus femoral approach because I don't think that makes a huge difference in terms of the actual outcomes. It's just patient preference at that point, but what catheters and wires to use, what your endpoints should be, perfected or not perfected, what size particles, we should do coils, should use liquids, et cetera. Everybody's doing it a little bit differently. It's not reproducible and the data is not consistent. That's been the big knock from the urology standpoint.
When you look at a TURP or an Aquablation or any of these minimally invasive surgical therapies, they're all done pretty much exactly the same way. There isn't a lot of room for artistic interpretation, if you will, for these cases when the urologists do them. When they have these large series, like everybody's trained up and they're all doing it the same way, we need to approach PAE with the same rigor. I think the best way to do that is to follow the data. We have a lot of long-term data, as I mentioned, from the Brazilian and Portuguese groups as to what the best techniques are and how we should be doing them, and what size particles to use and the techniques.
We should be implementing all of that because that's our best long-term data. If everybody's doing it that way, I really feel strongly that we can get the numbers that we should be getting in all these cases and getting the outcomes that make it very comparable to urologic therapies and very consistent.
[Dr. Michael Barraza]
What do you think is the best means of educating, I don't want to say the public, but the IR community on really what this way is, the best way to do this moving forward? I mean, are we talking about, I don't really know the right way to inform everybody what they should be doing.
[Dr. Sam Mouli]
Yes, let's use this podcast and do it right here. Just being a little bit facetious, but the big studies that we have, all of them pretty much start off with data from 300 to 500-micron particles. My standpoint is everybody who's doing it, if you're going to do a de novo PAE, not a repeat treatment, not somebody who's already undergone surgical therapy and has a recurrence of symptoms, just a de novo, new PAE patient, all of the data points to 300 to 500, so that's what you should be using in those patients. Just stick to that. There's a lot of safety there.
It shows really good efficacy with a really, really favorable side effect profile. So why change any of that up? I think there's been isolated reports and it is what I've seen from my own experience is when you get a little bit smaller in the particles and when you're going down to the smaller size of like 1 to 300 or so, you certainly get a better infarction that is without question, but you start to get a few more off-target effects and more risk of sexual dysfunction. I think one of the big positives for PAE, you let a lot of patients respond to is the minimized risk of sexual dysfunction. Basically, no risk of sexual dysfunction if done.
[Dr. Michael Barraza]
Absolutely. One of our biggest selling points.
[Dr. Sam Mouli]
Exactly, exactly, exactly. What I've seen is when you use a really small particles, you basically infarct the center of the gland, maybe it peels off and you're basically done an endovascular resection of the prostate. Yes, it's a great response. They're going to prograde, but they're also going to have retrograde ejaculation, so do we really, really want that? I would argue no.
[Dr. Michael Barraza]
No, and is it even necessary that that extra level of infarction? We've seen the same thing with fibroids, try to go smaller. Is it necessary, you still get good results with 300 to 500?
[Dr. Sam Mouli]
Exactly. If we're really pushing safety and much more favorable side effect profile compared to the other options, I think it really is contingent upon using that kind of technique. I think that's one of the big ones because everybody's always feels a little bit differently about what size particles to use and that potpourri of flavors and stuff.
(3) The Case for Early Prostate Artery Embolization
[Dr. Michael Barraza]
Let's go through some of the other controversies that you had mentioned in your email. The first one was, we're going to call it controversy number one like you did in your email. PAE should be considered alongside medical management.
[Dr. Sam Mouli]
If you look at the AUA guidelines and what practices and what our understanding is, and so they branch off the treatment pathway in that patients can go after they declare that they have BPH with lower urinary tract symptoms and they are indeed symptomatic. They can start on medications like Flomax and finasteride, so 5-alpha-reductase inhibitors and alpha-blockers. However, everybody knows that patients don't really tolerate these medications. They get really bad side effects and the failure rates are higher with larger glands.
A lot of urologists are opting for what's called early surgical intervention, where they basically push for getting a patient to surgery when they have the right indication. They have a large gland, they know they're going to fail medical management, et cetera. So why wait to treat them and know that their symptoms are going to progress and just get early treatment for their BPH and lower urinary tract symptoms? If we know that's already happening in the surgical space, it would make sense that you could do the same thing with embolization. Obviously you make sure that the patient does indeed have BPH and LUTS and why not go straight to treatment instead of prolonging things when you know they're not going to work?
[Dr. Michael Barraza]
I think it makes a lot of sense and I think you can very easily make the argument, especially for a really large gland, you know those symptoms are coming, you know it's not going to fully improve with meds. I think that makes a lot of sense and especially there's a time factor too. I mean, that these people are in the meds for usually a good while before we get to the treatment part.
[Dr. Sam Mouli]
Yes, exactly. So why prolong that? Why have the side effects and the potentially the progression in adverse events that can occur with just keeping patients on medication from a urinary retention standpoint or UTIs or other things when you know it's not going to work in a big gland and just get them to early treatment?
(4) The Role of Urologists and Patient Self-Referral in PAE
[Dr. Michael Barraza]
I completely agree. All right, so the next one I have for you is, should PAE be performed only alongside a urologist, not in the same room, but basically, patient who's already seeing urology? I'll tell you to start off when I started doing this, I felt very strongly that I needed to have urology on board. I went out and spent some time with Ari when he was still at UNC maybe five years ago and saw how they were doing it and I came out of there convinced it's like this is the way they follow up with urology.
Then I got into practice and I just waited and waited and continued to wait for any referral from urology. I did a lot of work trying to get these referrals, do a lot of good work outside of the prostate space with these guys and nothing came. What I started to see was a lot of self-referred patients, and some of them were already seeing a urologist, some were not interested.
Sam, for me, I've got where I haven't really had much of a choice. Some of these I just have to deal with on my own. I've got a urologist that I can refer to for anything like that, but I am kind of interested in getting your take on it. I'm sure you guys have a very robust relationship with urology there, so it's a little bit easier for you, but I'm sure you find self-referred patients too.
[Dr. Sam Mouli]
Speaking openly, probably 75% to 95% of my practice is self-referrals, honestly.
[Dr. Michael Barraza]
Wow. Okay.
[Dr. Sam Mouli]
Most patients, what I've found is unlike fibroids and gynecology, most men have a transactional relationship with their urologist. This is something I learned from Bob [unintelligible 00:15:05] saying, actually. You only really go and see your urologist when you have a problem. You're not seeing them after childbirth for your whole life, and so a lot of men are not wedded to continuing to see their urologist. Once they have the diagnosis of BPH, they're looking for all their options. Totally reasonable to see them after that.
[Dr. Michael Barraza]
When you get a patient who self-referred, do you have them see urology as well?
[Dr. Sam Mouli]
Typically, what I've found is, and I think it's probably different everywhere, is a man will not show up in my clinic unless they've been told they have BPH and they've been diagnosed with it because otherwise, they have no reason to see me.
[Dr. Michael Barraza]
Okay.
[Dr. Sam Mouli]
They're a very well-educated population in general. They know what the treatment options that are out there, they've been told about TURP or other invasive surgical therapies and they're like, "It doesn't really sound like that's what I want to have a scope, et cetera." I won't get too vulgar on the podcast. They already know what they're in for and so they've already educated themselves and that's why they've come and seen me. I typically have patients who have already had the diagnosis of BPH. That being said, occasionally, you see ones that somehow find you anyways and I do like them to see somebody to confirm in the EMR.
[Dr. Michael Barraza]
I'm with you.
[Dr. Sam Mouli] Yes, BPH. Not neurogenic bladder, not something else.
(5) Pre-Procedural Imaging for Prostate Artery Embolization
[Dr. Michael Barraza]
Totally. It's been a challenge debating for some of them that haven't or that travel from out of state, how much of the workup I need them to do and I haven't decided, I haven't really come to a conclusion on this like, do I insist that they get uroflow or not? I don't know. How important do you think uroflow is in the workup?
[Dr. Sam Mouli]
When we started doing all this in the beginning and this was stuff that Ari and Sandeep had pioneered early on in like the stream courses and such, that was like a big component of it. I think now that we've gotten more comfortable and there's a lot more data about PAE, is it really necessary? A lot of urologists will manage these patients based on clinical symptoms alone, AUA symptom score, and all these validated questionnaires. Maybe they have a uroflow in the office, maybe they don't, but they're not completely dependent on that for their treatment, and so I don't think we should be either, as long as they have the true diagnosis of BPH, this should be sufficient.
[Dr. Michael Barraza]
I'm with you, Sam. All right, well, here's the next controversy then. What about pre-procedure imaging? Do you ever do this without any pre-procedure imaging? I usually get something if I haven't looked at the prostate. I guess you should make the distinction between pre-procedure vascular imaging or any imaging of the prostate. Kind of interested how you feel about both.
[Dr. Sam Mouli]
The big thing here is, and I know things are different elsewhere in the country, it really depends location to location. Imaging is not typically part of BPH workup. It's not considered standard of care. If a patient goes and sees a urologist, he's not getting an MRI, he's not getting a CT scan to tell his prostate is big unless he has some other indication, cancer, hematuria, something like that. It's not part of the typical workup. If they come to see you and you want to get a CT scan or an MRI or whatever, it can be difficult to get that covered by insurance and then your patient is left with an out-of-pocket cost.
Truthfully, all these minimally invasive surgical therapies are all being done, for the most part in the community, without necessarily getting all this high-level cross-sectional imaging that we would require for IR. That being said, lots of groups have shown regardless of prostate size, you can treat these patients as long as they have the right inclusion criteria in terms of symptoms. I would argue that with enough experience and the right equipment, you shouldn't need cross-sectional imaging to be able to take- a patient to angio and treat them, especially since it's not part of their regular workup and you could be leaving the patient with a cost that they'd have to cover themselves.
[Dr. Michael Barraza]
I'm with you. I agree. Most of the time it doesn't add much. I hate to be too anecdotal on here. Two of my last patients that had been referred, I got imaging on them, and the first one had the tiniest prostate that I think I've ever had referred. It was so small. It was like I just don't think I'm going to be able to really add much for you. The other got a bladder full of stones. Again that's very rare.
(6) Cone Beam CT in Prostate Artery Embolization
[Dr. Michael Barraza]
To take this a step further, let's talk about cone beam CT. That's technically pre-procedure imaging and you had brought this up, it is something we should talk about and I agree. A lot of people just going straight to angio doing the embolization and that's it. You and I both agree on cone beam CT.
[Dr. Sam Mouli]
I think in the beginning, cone beam was deemed as something to make sure that we are indeed in the prostate, you're not embolizing the bladder, you're not embolizing some other structures, and that that it was like a confirmatory tool. What we found from the initial experience on a lot of the reported literature is cone beam's really valuable, not just for that, but also identification of other supply and collaterals, and so early papers have reported collaterals in the realm of 20% to 40% of patients. I think in my own practice I see them in 60% to 70% of patients.
[Dr. Michael Barraza]
Wow.
[Dr. Sam Mouli]
So why is that important? When I take somebody to angio, what I tell them is, I want to get you to a five-year success rate that matches Tiago's work and matches Carnevale's work, which is basically in the recurrence rate is under 20%. In order to do that, you want to treat everything that's going to the prostate at the same time, identify the major blood supply, but any collaterals that might crop up, and then feed the gland after you've done the embolization. To do that, I really rely heavily on cone beam to make sure that there aren't actual prostatic sources that I need to coil off and such. Yes, I see those in 60% to 70% of cases and I'm doing a lot of coil embolization before we do the particle embolization to facilitate that.
[Dr. Michael Barraza]
You're able to see them a lot of time on your cone beam CT. I don't think that gets talked about enough is using cone beam as a tool to identify collaterals that either need to be embolized or something you got to look out for during the treatment.
[Dr. Sam Mouli]
The way I've been using cone beam, and I think a lot of people started doing it this way is rather than using it once you get into the prostate, I do like basically a pelvic cone beam CT to get a lay of the land, the anatomy, and then look at everything that is going towards the gland. My, "search pattern" for this is I look at what's perfusing the penis on both sides first and then making sure that there isn't a distal pudendal branch that's coming back up towards the prostate or feeding the prostate." Once I've cleared that, if there is, then I try to get into that and coil it off, to begin with. Once I've cleared that, then I look at what's going to the gland on both sides.
Is there stuff from the rectum, stuff from the bladder, et cetera, where's the origin? Then trying to treat all of those vessels at the same time. What we found is once you get over 80 to 100 grams, you're usually going to have two arteries on the right, two on the left, some asymmetry that you just got to get into all of these different vessels.
[Dr. Michael Barraza]
Are they usually big enough to identify the ones that you're going to have to treat, or are they hard to distinguish from some of these collaterals, as you said, from a pudendal that you would coil rather than infuse particles through?
[Dr. Sam Mouli]
Yes, so basically what my goal is to get into all the little ones, if they are several, coil all those off, basically skeletonize the gland, so to speak, and then get into the main supply embolize that with particles to stasis.
[Dr. Michael Barraza]
Going after those at the beginning rather than during your treatment, do this prostate, pelvic and prostatic arteries, do they respond the same way they do in the liver where you could do an embolization and then 30 minutes later, you get redistribution of flow into the rest of the gland?
[Dr. Sam Mouli]
Yes, so that's basically what we've seen in our own experience and then in others have reported this that where do early recurrences come from? It's usually these collaterals that you either didn't treat the first time or didn't see or you missed or whatever. Now, I'm just really vigilant about getting into them, coiling them off up front such that once you treat the main one, you're getting feeling that inflow is cut off, so to speak. You're getting filling of the whole gland. You're not having any missing pieces, et cetera. It's like, as I'm doing the case, it's like a jigsaw puzzle, and I'm trying to piece it together side to side and make sure everything is covered and not missing anything.
[Dr. Michael Barraza]
Do you ever see these collaterals that are big enough that you decide you need to particle embolize as well?
[Dr. Sam Mouli]
Yes. I think the key is you see how much tissue it's perfusing, what's its size relative to your microcatheter, and then when you inject, are you getting antegrade flow, or is it mostly refluxing into territory that you don't want to treat from? One way is you can just do that with the catheter. The other things that I found is using vasodilators, nitroglycerin, verapamil, things like that can help you and redirect the flow such that you can embolize with particles from these collaterals if it's appropriate, and then coil them off when you're done.
[Dr. Michael Barraza]
Now, one more question about cone beam. Not using it so much anymore to confirm. Do you ever do them after you get the microcatheter in and do another one to show how much gland you're perfusing?
[Dr. Sam Mouli]
Typically not. I think the pelvic cone beam gives you a really good lay of the land. Just from a time standpoint, if you want to just move and be efficient, you can estimate from angio how much land you're covering once you've picked everything off that you need to. I think early in your experience, in your first 20 cases or so, you really need it. After that, it gets really second nature.
[Dr. Michael Barraza]
Yes. I'm not at a point where I am interested in getting rid of cone beam in really any sense. Certainly not at the beginning. I'm doing them the way you are. Asked our friend Dave Johnson his protocol and stolen that, for me it's invaluable.
(7) PAE Technique: Embolic Agents, Collaterals & Vasodilators
[Dr. Michael Barraza]
Okay, let's move on again. Let's talk about embolic agents to use for PAE. You had mentioned that you prefer 300 to 500-micron particles. That's what I'm using as well. Just for me, it's just that in coils, you hear about people using liquid and bollocks. You would mention that and smaller particles. Are there ever any circumstances where you're using either of those, anything smaller or liquid?
[Dr. Sam Mouli]
No, not really. Not after all the data that's been out there for smaller. Unless you have a patient that you're retreating for whatever reason or they've already undergone previous surgical therapy and then those vessels can get very dicey and they're very small. We've had good results in patients that we've retreated after UroLift failures or GreenLight failures or other things like that, but those vessels could be smaller and friable and thus require different tools. In those cases, the other thing that we've noted, and we'll be publishing this pretty soon, I think we shared it I guest last year, is those patients tend to have a lot more collaterals.
[Dr. Michael Barraza]
Interesting.
[Dr. Sam Mouli]
You have to be really vigilant about coiling and looking out for non-target embolization in those patients because after they've been resected or partially resected, what have you, the blood flow and vascular anatomy changes quite a bit.
[Dr. Michael Barraza]
That's interesting. I didn't realize that after UroLift, et cetera, they get more collaterals. I don't think I've had to retreat any of those. You mentioned that those arteries can be a lot more friable and presumably more torturous. How are you treating them differently?
[Dr. Sam Mouli]
All of the same tools we talked about with cone beam and everything like that. Aggressive with the vasodilators, very aggressive with coil embolization because we find collaterals to the penis, bladder, rectum, everything that you can imagine, they're going to be collaterals, basically. The vessels are usually much smaller and more wispy and friable. There's a lot more instead of a big single artery, there might be a lot of tiny little branches going to the tissues. It can be very challenging, but the patients do really well after the treatment. It's just a little bit more meticulous work is required to do it safely.
Very liberal with use of coils, very liberal with use of vasodilators, and getting a lot of good angiographic images to make sure that you're not hitting anything that you don't want to hit in the wrong target bed.
[Dr. Michael Barraza]
Let's talk a little bit more about collaterals. You've already told us what you do for the ones that you identify in cone beam CT that you embolize before going after the main arteries to the gland. Let's talk about how you approach the ones that pop up during your treatment, during embolization, the ones that you see when you do your run after. How do you decide which ones need to be embolized? What do you do if it's something you can't reach?
[Dr. Sam Mouli]
That's a great question. When I initially started out doing these, I would give a little bit of particles, 3 cc Medallion or something like that, then do a run a little bit more and then do a run. Probably the doses were way too high.
[Dr. Michael Barraza]
Mine are still there.
[Dr. Sam Mouli]
Yes. You're like, "Oh no, what do I do with that?" Exactly. Like, "Do I go after it? Where is it going? Is that going to the penis? Is it going to the bladder?" Getting a lot of anxiety from that. What I've found is I do the cone beam upfront. I identify what is hemodynamically significant, that it's lighting up as a collateral upfront before you've done anything, before you've changed the flow dynamics, take care of the ones that I need to take care of, get into the prostate, give a very liberal dose of nitro, something around 200 mics per side or more, followed by verapamil.
The verapamil idea is in line with some papers that have been written and also what's been reported with like balloon microcatheter experience in that if you create a low-pressure vascular bed in the prostate, any of the other vessels are like protective inflow. Instead of you injecting and then the contrast going out the collaterals or the flow going out the collaterals, now it's low pressure in the prostate, so the flow is coming in from everywhere.
[Dr. Michael Barraza]
Okay.
[Dr. Sam Mouli]
As long as you embolize really slowly in that low-pressure state, you shouldn't see anything go out. I dilute my particles in 20 ccs of straight contrast and then I inject with a really big syringe. I'm forced to go really, really slow.
[Dr. Michael Barraza]
Okay.
[Dr. Sam Mouli]
When I started out, it was hard to get into the prostatic artery and that was all the time in the case. Now it's like getting in, in five minutes, and then embolizing for 25 per side and just going really, really slow. Then as long as you don't see reflux distally from the catheter tip beyond the prostate, I don't do another run until it's static. It's worked out really well from that standpoint. I sleep at night better. It's a lot simpler.
[Dr. Michael Barraza]
Dude, just using 300 to 500-micron particles also helps me sleep a whole lot better knowing that a couple of those little guys are probably going to leak out there. It seems to be pretty well tolerated with 300 to 500-micron particles.
[Dr. Sam Mouli]
Exactly. All the cadaver studies and basic science studies in the space have shown, what is the vessel size of these different organs that you want to avoid, basically. As long as you're in that range, the likelihood of you damaging those other structures, as long as you don't directly inject the penis or the bladder or something like that very, very low. Just go real slow. The slow, steady embolization I found works really, really well. Then I don't have to do multiple runs in these patients and the outcomes are just as good as how we were doing it previously.
[Dr. Michael Barraza]
Man, that's super helpful. That's going to change how I approach these.
[Dr. Sam Mouli]
Take good pictures upfront and then just stop after that. Take your time with the embolization. It's much, much simpler.
[Dr. Michael Barraza]
Oh, it sounds like it. Certainly, that's one thing about my own performance it needs to change or my dose rates are pretty high. I think a lot of that comes from those runs in the middle. Yes, I look forward to making some adjustments. No need for perfected technique in your practice. I'm personally not advancing it any farther after I get there, but–
(8) Advanced Techniques in Prostate Artery Embolization
[Dr. Sam Mouli]
Yes, so that's a good question. What were the end-points imperfected. You start proximal, then you go distal, if you've already taken it to stasis, how do you know when to stop? Some of the endpoints with perfected are like weird blush, vessel rupture, things I just don't really feel comfortable seeing on an angiogram. What I've done more recently and with this newer generation of microcatheters from Boston and Terumo and everybody is you can get really deep up front.
Then I just get as far as it wants to go and then basically start embolizing, then embolize all the way back until it's static up to where I think it's safe that there's not going to be any reflux anywhere. Get really deep as far as you can go up front and then just embolize.
[Dr. Michael Barraza]
You can take a true select almost in the gland.
[Dr. Sam Mouli]
I've taken it to the other side.
[Dr. Michael Barraza]
Wow. That's cool. After you do your embolization with the 300 to 500-micron particles, do you use gel foam or anything else or just particles and go?
[Dr. Sam Mouli]
Just particles and go typically. The only time I'm adding anything else is in the patients with hematuria or something like that, that are coming in because they're bleeding and they are having clot retention and things like that. I get more aggressive with either gel foam or more typically with coils. Because in those guys, a lot of times they're on blood thinners. They got to get back on them for their heart or what have you. I don't want them to ever, ever bleed again, and so that's when I'm "coiling out". Otherwise, I'm pretty anti-coiling out, which we can get into.
[Dr. Michael Barraza]
Let's get into that. Sam, I guess what I don't understand and it's not something that I do in my practice. Tell me the rationale for coiling out, I guess for our listeners. What is coiling?
[Dr. Sam Mouli]
I don't want to speak to it too much because I don't do it, but it's a technique in that you embolize the prostate to stasis and then you coil the parent vessel when you're done such that there's a better infarction, less perfusion to the gland, and more permanent embolization if you will. Now, is there a long-term data showing that that's the better way to do this? No. It hasn't happened yet. Maybe there will be, and maybe I'll be proven wrong. That's a possibility. I think if you take a more global view of BPH, BPH is a hormonal process. Its growth is because of testosterone, is stuff like that bloodstream, and we are not taking that away from patients, not with TURP, not with embolization, not with anything.
Really the only way to prevent regrowth of the gland is complete surgical removal with radical prostatectomy. Even with TURP, the natural history of the disease is such there's probably up to a 20% chance of recurrence at five years requiring either medical or surgical therapy. You know the gland's going to regrow, why not leave yourself an option to get back in and retreat because, on a long enough time scale, the patient will need retreatment?
I don't think you can ever get complete perfect embolization. That's never going to require treatment again. I think that's very unlikely, and so why not facilitate a retreatment in patients? Because I think if you ask a patient their options if they did really well with their first PAE and 5, 10 years later they need a second one, I think they would opt for that rather than going through a TURP or any other more invasive surgical therapy.
[Dr. Michael Barraza]
Personally, I guess I don't believe that the coil adds much to the embolization, at least not in the sense that it's going to cause much further gland infarction. When you think about it, half the time you're doing these patients have atherosclerotic stenosis and the vessel you're trying to treat and inflow, I don't really think so much as the issue. You're getting flow from all these other branches as well.
[Dr. Sam Mouli]
Exactly. I don't think it adds much and I think it only creates a difficulty if you have to go back in and retreat the patient. That being said, if they're coming for hematuria and they're bleeding, and you really want to make sure that they don't bleed again, especially if they have to go back on anticoagulation. Those patients, I will coil the parent vessel.
[Dr. Michael Barraza]
Okay. That makes a lot of sense.
[Dr. Sam Mouli]
To the same end, that's why I don't really think there's a really good role or justification for liquids in this space. Because if you think about it, a liquid is very similar in the way it works to a coil and you're just really occluding the main branches, you're pretty much guaranteeing that you're never going to be able to retreat this patient. When we know that the natural history of the disease is such that they will likely require retreatment at some point, and so why do that and not be able to offer this therapy again to the patient if it's so advantageous from a safety and side effect profile?
[Dr. Michael Barraza]
Totally. It's more proximal embolization than particles. For me, I don't have a role for it.
(9) Retreatment Rates Following Prostate Artery Embolization
[Dr. Michael Barraza]
Sam, the next thing I have for you, and this is the last question that I have unless you've got something else that you want to talk about, is the next controversy you brought up, retreatment rates depict a false narrative of PAE utility. We touched on this a little bit, but I want to take it a little bit further, and just have you run through this one.
[Dr. Sam Mouli]
The big knock against prostate embolization is that when urologists look at the data, especially from the RCTs that were published out of the Swedish trial and others, there was a 20% retreatment rate at one year. Then they're like, "Well, it doesn't work in a large number of patients." Then looking more globally at the long-term data that we talked about earlier in the podcast, at 5 to 10 years, there's probably also a 20% retreatment rate, and so what are these retreatment rates?
I think the early failures are really contingent upon technique. How are you doing it? Are you identifying all the vessels? Are you treating both sides of the gland? Those early papers, those big RCTs that the app trial and such, a large number of patients were only treated with unilateral embolization. Hence why they have recurrence of symptoms very, very early. It makes sense. You've treated on one side, we know that that's not going to work. Same thing with the UK-ROPE trial, and so when urologists bring up those issues, that's basically the argument can be made. That's like doing half a TURP, or half a Rezum, or Aquablation. Of course, it's not going to work.
The long-term retreatment rates really speak to the natural history of the disease. I don't think it's possible to get a retreatment rate that's zero, and when you compare PAE to other minimally invasive surgical therapies and there are a lot of nice systemic meta-analyses that are both from the PAE literature and also the MIST literature, they all really show that the long-term retreatment rates for both groups of therapies are in the 10% to 30% range at 5 to 10 years.
[Dr. Michael Barraza]
Interesting.
[Dr. Sam Mouli]
Lines up pretty nicely. PAE has a retreatment rate of that, so do all the other MISTs. It's really consistent. If we have this similar retreatment rate and we know what the natural history of the disease is, why wouldn't you want to choose something that is less invasive, has a better safety and side effect profile, and won't affect sexual function rather than something that's more invasive, and so I think that's a better option for patients.
If you were to counsel them appropriately and present everything like this, I would argue that a patient would rather undergo something like a PAE and preserve his sexual function early on and then progress if he needs to, to something more invasive later on in life. Or have a repeat PAE if he needs to, rather than move forward to something more invasive surgically.
[Dr. Michael Barraza]
Man, I think you just nailed that one. One of the benefits of this, this does not take anything off the table for any further treatments. We do this, you are still available to have any of the other treatments that are out there after this. This does not stop anything. Sam, that's about all I got. Is there anything else that you want to talk about?
[Dr. Sam Mouli]
I think we covered a lot. I think I'm very passionate about this space and this technique, and I really think we're doing a good job as a specialty of really trying to bring it to as many patients as possible. I think the next goal, as we touched on as a group, is we just have to really agree and draw a line in the sand of, "This is how we should all be doing it." Let's all agree to do it the same way. Maybe that comes in the form of guideline documents, et cetera. That way everybody's doing it the same way. The results are very reproducible and patients can have really good outcomes.
Why do I think that's achievable? If you compare the long-term data from the Portuguese group and the Brazilian group, they're very similar, and those are guys who are high-level operators who are doing it exactly the same way for case-in-case-in-case-out. We should be doing it the same way. In our own experience, we've tried to adapt those techniques and we see similar outcomes. I think it's conceivable that everybody can do it this way. Everybody can have very similar outcomes and then a patient can look at the data, and make an informed decision knowing that it's not really contingent upon what particle the further uses or microcatheter, et cetera.
It's going to be a reproducible result, and they can rest assured that they know what they're getting into.
[Dr. Michael Barraza]
I'm with you. I think that's a great way of putting it. Sam, thank you. I really appreciate you taking the time out of your day to join us, and I look forward to begging you to come back on, once you publish some of this new data you guys have coming down the pipe. Thank you and thanks again to our listeners and we'll catch you guys on the next one.
[Dr. Sam Mouli]
Thank you. Take care.
Podcast Contributors
Dr. Sam Mouli
Dr. Samdeep Mouli is an Assistant Professor of Vascular and Interventional Radiology at Northwestern University Feinberg School of Medicine.
Dr. Michael Barraza
Dr. Michael Barraza is a practicing interventional radiologist (and all around great guy) with Radiology Associates in Baton Rouge, LA.
Cite This Podcast
BackTable, LLC (Producer). (2023, January 9). Ep. 280 – Current Controversies in Prostatic Artery Embolization [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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